Italy's Red Olives

In most cases, olives are green of blackish. On Malta grows a rare variety that produces white olives. See here. But there's also a red olive.

The Bella di Cerignola ('beauty of Cerignola') is an olive cultivar, which originates from the south-eastern Italian province of Apulia and is named for the town of Cerignola. The cultivation of the Bella di Cerignola, reputed to be the largest table olive in the world, has ancient origins. Some authors believe that this cultivar derives from the 'Orchite' olives used in ancient Rome.

According to some it was introduced around 1400 AD from Spain, which might justify its now obsolete synonym of 'Oliva di Spagna'. According to others, however, the synonym simply derives from the type of curing used in Cerignola, which is called the 'Spanish' or 'Sevillano' method. However, since no closely related cultivar has ever been found elsewhere, it can be considered a native variety of the Cerignola area.

But how do green olives turn into red olives? The secret is a food dye called erythrosine (or E127). Which is a bit of cheating nature. The black olives are created by soaking them in ferrous gluconate.